1. Field of the Invention
This invention relates to key controlled locks and has particular reference to inexpensive key controlled locks effective, for example, to control electric switches.
2. Description of the Prior Art
Key controlled locks of the above type having adequate safequard features to prevent unauthorized operation without a key of proper configuration, have generally been of the tumbler type, including a cylinder, a key receiving plug within the cylinder, and locking tumbler pins carried by the plug and settable by a key inserted in the plug to unlock the plug from the cylinder. Such locks generally embody small springs, tumblers, and other parts which must be precision manufactured to close tolerances to insure proper operation. Also, the parts must normally be made of relatively expensive materials and must be properly cleaned and lubricated to prevent malfunctioning due to corrosion, rust, etc.
Also, particularly in connection with electronic processing equipment, such as electronic cash registers, where key controlled locks are often employed to prevent unauthorized use or to establish certain modes of operation of the equipment, the use of metal key locks on the equipment may allow static electrical charges to be transmitted to certain of the sensitive electronic circuits and components which could cause malfunctioning or even damage.